Chapter 5, Problem 34P

|| Measuring the coefficients of friction. One straightforward way to measure the coefficients of friction between a box and a wooden surface is illustrated in Figure 5.55. The sheet of wood can be raised by pivoting it about one edge. It is first raised to an angle 81 (which is measured) for which the box just begins to slide downward. The sheet is then immediately lowered to an angle 92 (which is also measured) for which the box slides with constant speed down the sheet. Apply Newton’s second law to the box in both cases to find the coefficients of kinetic and static friction between it and the wooden sheet in terms of the measured angles _θ1 and θ₂.

Figure 5.55

Problem 34.